Are space agencies investing enough in Earth Observation?

ENVISAT photographed in orbit by Pleidas, 15th April 2012

Envisat, the Eurpean Unions’ flagship earth observation satellite, stopped communicating  with ground stations on 8th April 2012. Though it is still in orbit, and appears intact (as this incredible image from Pleidas – a normally earth-facing satellite that passed within 100 km of ENVISAT on the 15th April –  showed), the European Space Agency has now given up attempts to make it respond to ground commands. This triggered the Economist to write a Leader bemoaning the lack of investment in Earth Observation satellites for environmental monitoring by the EU and the USA, the two dominant traditional players. Envisat has provided over 10 years of consistent data on many aspects of the earth system, its 10 instruments providing data from areas as diverse as sea-ice extent, atmospheric composition, landcover change and ocean temperature. All these appear to be changing rapidly (indeed more rapidly than the most pessimistic scientists used to predict), as they represent different aspects of global climate change: whatever an individual’s views are on the cause of these changes, it is hard to argue against the importance of collecting consistent global data to study the trends.

The worrying thing is that even though Envisat was 5 years beyond its 5-year design life, there is no replacement in orbit. Many of its functions are covered to a certain extent by sensors on other satellites. But some functions are not duplicated at all, and none collect data directly comparable to the sensors on Envisat. This will at best result in long-term environmental datasets having added uncertainties due to issues of cross-calibration and changing metrics, and at worse result in large data-gaps.

Image copyright ESA & ASTRIUM

The EU had aimed to secure Envisat’s legacy through the Sentinal satellite series, a series of operational satellites planned through  Global Monitoring for Environmental Security (GMES) program. However the first of these will not be launched until 2013; and they may be further delayed due to a lack of commitment from the EU to pay their considerable operating costs. I don’t want to criticise this program too much though: provided the funding can be guaranteed, the GMES Sentinel series mark a big step forward in this area, envisaging new satellites being launched every 3-4 years to ensure that these essential climate variables are monitored consistently into the 2030’s and beyond. This is in sharp contrast to the USA, which has been consistently reducing its (still considerable) civilian earth observation budgets over the last few years. Indeed, Professor Dennis Hartmann of the University of Washington, who led a report on the subject, stated in May 2012 that:

It’s likely our capabilities will decline fairly precipitously at just the time they’re most needed. If nothing is changed, we’re predicting to be down to 25 percent of our current capabilities by 2020.

There must be a hope among policy makers that private companies and developing countries will help make up the gap. This is likely to work to a certain extent: for example sub-meter resolution imagery is now widely available due to a series of satellites produced by GeoEye and DigitalGlobe.

Image of Dakar, Senegal, captured by the WorldView-2 satellite. Sample image provided by DigitalGlobe.

Other commercial companies, often in collaboration with universities and research institutions, can also now produce satellites at a very low cost, leading to for example the Disaster Monitoring Constellation and Cubesat initiatives (more about these in a later post). Finally emerging economies are indeed putting many satellites into orbit, most notably China, India and Brazil. But these satellites will only be put up there for reasons of commercial returns, research interests and national priorities respectively: for example China has an is launching a large number of satellites to monitor the disputed seas around its coast, and Brazil runs the CBERS satellites (developed in partnership with China) to monitor its forests. What these will not do is provide the long-term consistent measurements of the earth system that are needed to monitor our changing planet.

Envisat could continue orbiting the planet for 150 years before re-entering the atmosphere, provided it does not hit one of many pieces of space junk identified to pass nearby and spread its 8 tonnes of components across its orbit. But the question is whether governments will wake up to their responsibility to continue its legacy and measure the basic variables consistently throughout that period.

I leave you with one single striking image from one of the 10 sensors on ENVISAT.

This shows the carbon monoxide concentration globally over a single year from the SCIAMACHY sensor. The sources of carbon monoxide from African fires and SE Asian industry are especially obvious; but no directly comparable data will be collected this year nor in the near future.